Energy content of foods

Variables in experiement

Independent: The independent variable is the different food substance used

Dependent:  the dependent variable in this experiment is the difference in rise of temperature for each food substance.

Control: The control in the experiment was the volume of water and the distance between the ignited food substance and boiling tube.

                                                          DATA COLLECTION

Table 1

Table 2

Table 3

                                                                                       

                                                                   

                                                                              DATA ANALYSIS

Figure 1

Figure 2

Interpratation/Discussion

Observations:

Cheese ball: The cheese ball ignited easily, and stayed alight for a while before it had to be relighted. It burnt with a fairly bright and large flame. However, it completley burnt out, turning black, very quickly, and was the fastest food substance to burn completly and released the highest amount of energy (3124.8j)

Twistys: The twisty crisp, burnt with a bright and large flame, it took two tries to ignite it however once it was ignited it stayed on fire this was mainly due to the fact that it was dry hence lighting it was no problem. It burnt out very quickly as the cheese ball was small and dry. A thin trail of smoke was visible.

Bread: The bread took several tries to light, and once it was lighted, it needed to be relighted a few dozen times in order to keep it burning as it was fairly damp and very thick. It only emitted a low flame and lots of smoke this was again due to its dampness. It took a long time in order to completly burn out as it was quite thick. It can be seen that the bread gave the lowest average increase in temperature (only 2.8 °c)    

Biscuit: The biscuit burnt with a medium flame which was a lot brighter than the bread yet not as bright as the Twisty. It emitted a steady stream of smoke, and took quite a while to completly burn out as it was a large piece of food. The biscuit was (as can be seen from the above results) the food substance which caused the most drastic change in temprature. (48.8 °c)Although this was mainly due to its large mass rather than its energy content as can be seen in table 3 it actually contains the second lowest amount of energy (1261.2j).

Evaluation:

There were alot of factors which affected the results obtained from the experiment.  A large amount of heat was lost to the surrounding air thus lowering the temperature reading.  Another factor affecting the experiment was the oil/grease which dripped off some of the foods used. The oil/grease contained extra energy which unfortunatly could not be measured hence affecting the results obtained. However even though these problems were encountered enough data was collected in order to make a conclusion.

Suggestions to improve: I feel that if given a wider range of food substances and more time, more data could be extracted from the experiment. Also if all the food substances had nutritional information on the pack like the twisty and cheese ball it would be easier to conclude how accurate my hypothesis was.

Conclusion:  

My hypotheses were correct. From the above experiment it can be concluded that the cheese ball provided the most amount of energy, due to its high fat content. With the twisty close behind then the biscuit. Then with the least amount of energy, the bread containing high carbohydrate and low fat content.